else if (getEnclosingDefinition() != null)

      return getEnclosingDefinition().getNamespace(name.substring(0, index));

    Definition enclosingDefinition = getEnclosingDefinition();

    else

      return null;

    String namespaceURI = null;

    if (enclosingDefinition != null)

    {

      String prefix = name.substring(0, index);

      // First try to locate the namespace URI in the definition's prefix to namespace map.

      // This will provide backward compatibility for existing clients.

      namespaceURI = enclosingDefinition.getNamespace(prefix);

      if (namespaceURI == null)

      {

        // We did not find it at the tope level, try to find a locally defined namespace prefix.

        namespaceURI = getNamespaceURIFromPrefix(element, prefix);

      }

    }

    return namespaceURI;